The advanced optical system of Panasonic PX-2 series reduces the dead zones in front of an automatic guided vehicle (AGV). The dead zones at the sides are further minimized if auxiliary sensors which can be easily mounted with connectors are used. Sensing areas can be selected with switches to suit the route conditions of an AGV. Further, in case of PX-24ES and PX-23ES, the sensing areas can also be selected with external signals. Its size is half of a conventional model, and the attached cable orientation is freely adjustable. Hence, it can also fit in a small AGV. Moreover, sensitivity adjustment can be done on the front face. Panasonic PX-26 has a long sensing range of 5 m 16.404 ft. Even on a high-speed AGV, it can detect an object quite early so that slowing down and stopping are smooth. The sensor can be put into the sleep (stand-by) condition when it is not used and can be restored to operating condition by an external signal. Consequently battery is conserved as the power consumption is reduced to 1/5. One PX-2 sensor can simultaneously receive beams from 25 Nos. of other PX-2 sensors without resulting in any interference. Even if AGVs are facing each other, the PX-2 sensor on one AGV reliably detects the other AGVs. Hence, it can be safely used even at a place where several AGVs are moving.